Intra-port traffic consists in moving containers between loading/unloading points of cargo vessels and temporary storage areas (linked to road and rail transport infrastructures). The loading/unloading phases employ mobile lifting means (cranes) that load/unload mobile platforms used for transportation between the various points of the port. The accuracy of the positioning of the mobile platform when parking it is crucial to accelerating the loading/unloading task and making it safe.
In fact, the operations of parking a platform or trailer, propelled by means of a motorized cab, are difficult and take a long time, even if they are carried out by experienced drivers. Accidents can also occur, putting in hazard the equipment contained in the containers and also the persons involved in manoeuvres round about. To increase the productivity and the safety of port traffic, it is therefore necessary to accelerate the parking operations and to reduce greatly the number of accidents. To reduce these accidents, it is necessary to load and unload the containers accurately, which requires accurate positioning of the platforms in the parking spaces.
To improve the accuracy and the safety of the operations of loading and unloading containers onto and from platforms, there exist parking stations equipped with lateral walls. The problem is then to park a platform, trailer or long vehicle rapidly in a parking area to an accuracy a few centimeters or even one centimeter. Assisted parking or automatic parking is necessary for this purpose.
One application example is to insert automatically a vehicle 13 meters long and 3 meters wide carrying a payload of the order of 60 tons into a parking space with a positioning accuracy of the order of one centimeter from a starting position around fifteen meters or more away from the parking space, parking area.
A number of more or less automated parking assistance solutions are known, but they have drawbacks or are unsatisfactory, or are not able to address to the stated problem.
The document EP 2 353 690 B1 concerns the same context and the same type of vehicle, with the same types of movement and parking areas. The control of the vehicle is nevertheless entirely manual and there is no mention of any requirement for accurate movement.
In the document U.S. Pat. No. 8,862,321 B2 a vehicle is guided along an initial target path by commanding a steering actuator until the vehicle is located in a particular position required for parallel parking. However, the vehicle concerned is different from that with which the present invention is concerned, and has neither the same dimensions nor the same kinematic. The trajectory and the required position are different. This approach does not satisfy the accuracy requirements.
The document DE202013011728 raises the problem of autonomous navigation of a vehicle in an exterior environment where navigating a container transport lorry in the port environment is part of the possible application contexts. However, the solution described in that document is not suitable for complex movement kinematics. It proposes fixed markers in the environment that indicate the path to be followed with sensors on the vehicle that identify those markers. In particular it has the drawback of requiring markers on the path of the vehicle, which makes implementation more complex.